Trays are generally used to transport potted plants, grow multiple varieties of plants, or for other commercial or agricultural purposes. The trays are usually created from one piece of material and may form a unit with multiple compartments for planting and storing seeds, plants, or to hold other containers. Plant trays may be set side by side in greenhouses, or other agricultural/commercial areas, and arranged independently of each other. In this arrangement, the trays are not connected to one another. If the user desires to collectively transport, sell or grow multiple plant varieties/sizes in a single tray, the various plants or seeds must be placed in the single tray. This can be difficult and inconvenient when having to relocate (transplant) a plant from its corresponding tray to the single tray. Accordingly, there is a need to provide a plant tray that is interconnectable with another tray, so that additional plants, or different plants, for example, may be added or combined with the existing tray by attaching to the existing tray a second or subsequent tray containing the additional and/or different plants.